Informatics Publishing Limited

Yan Xu ¹, Lei Nie ¹, Min Zhang ¹, Tong Wang ¹, Jiaxin Wang ¹

Affiliations
1 College of Construction Engineering, Jilin University, CN

Abstract

The Chaancun debris flow gully is located on the mountain slope of the crown of the Chaancun landslide. The hiking corridor, leisure square, Lvshun middle road, and Wangjiadian reservoir are situated below the debris flow track. The Chaancun debris flow gully poses a serious threat to the safety of this site and to the development of tourist attractions. First, an appropriate recognition of the debris flow gully is required by a field investigation. This gully is steep and straight. The weathered and denuded rocks coming from the fault zone are the debris source. In addition, concentrated rainfall occurs in this area. Therefore, the debris flow gully has the forming conditions of a debris flow. Many factors affect the formation and assessment of a debris flow, and they result in uncertainty, randomness, and fuzziness. Therefore, the fuzzy mathematics method is suitable for the risk assessment of debris flow. To improve the reliability of the risk assessment of the Chaancun debris flow gully, primary fuzzy assessment and secondary fuzzy assessment considering hierarchical analysis were undertaken for quantitative risk assessment. This gully was categorized as "extremely hazardous;" thus, appropriate mitigations such as building a concrete dam and planting in bare areas were designed and implemented.

Keywords

Debris Flow, Risk Assessment, Fuzzy Mathematics, Mitigative Measures.

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Huohua Li ¹, Shiwei Shen ¹, Yan Xu ¹

Affiliations
1 College of Construction Engineering, Jilin University, Changchun, Jilin-130026, CN

Abstract

Direct shear tests were conducted on frozen rock joints. The variations in the dilatancy features of these joints were investigated under the correlativity of different opening values and the maximum fluctuation degrees of the joints. Furthermore, a contrastive analysis of the dilatancy features of rock joints at freezing and normal temperatures was conducted. Results showed the total regularity of the "initial dilatancy and subsequent compression." However, different dilatancy features were revealed under different normal stresses when the opening value of a joint was smaller than its maximum fluctuation degree. The dilatancy amount of the joint reach edits maximum value under a medium stress level, and the final normal displacement increased as the normal stress increased. By contrast, only a minimal dilatancy effect was induced in the growth stage of the shear stress because of the ice microcrystalline particle dislocation, which occurred when the opening value was greater than the maximum fluctuation degree of the joint. Under the same normal stress, when the joint opening value was large, the amount of dilatancy was relatively small compared with that when the joint opening value was small, and the final normal displacement of the joint surface was relatively great compared with that when the opening value was small. The contrastive analysis results on the dilatancy features of joints under normal temperature showed the following: at a normal temperature, the dilatancy amount of the joint monotonously increased with an increase in the shear displacement, and the final dilatancy amount was larger than that under freezing conditions.

Keywords

Opening Value of Joint, Freezing, Shear Test, Dilatancy, Contrastive Analysis.

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